Area Forecast Discussion
Issued by NWS Wilmington, NC

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684 FXUS62 KILM 240011 AFDILM Area Forecast Discussion National Weather Service Wilmington NC 811 PM EDT Fri Jun 23 2017 .SYNOPSIS... Deep moisture will become increasingly squeezed by an approaching cold front through Sunday morning. Some drier air should move in later Sunday. More seasonable weather will return next week with isolated mainly afternoon thunderstorms. && .NEAR TERM /THROUGH SATURDAY/... As of 300 PM Friday...The KLTX 88D continues to be relatively echo free across the ILM CWA. The relatively pinned sea breeze is identifiable to a degree via the KLTX 88D. From hence on out thru sunset, would not be surprised for isolated convection to break out especially across the ILM SC CWA where the NVA aloft is not as strong or prevalent like across the ILM NC CWA. Will only carry isolated to widely scattered 15-25 POPs thru sunset followed by no POPs for the night-time period. Relatively oppressive, heat-wise, with sfc dewpoints in the mid and upper 70s and temps around 90 this aftn and evening. Only saving grace, is that the sfc winds will stay active this aftn thru tonight, and likely continue thruout the day on Saturday. The sfc pg will remain tightened thruout this period and will only show some signs of relaxing well inland during late Sat due to the approaching frontal boundary. With some decent forcing now avbl, will ramp POPS up big-time during Sat aftn which will mesh nicely with the even higher POPs slated for Sat night. With PWS back well over 2 inches by Sat aftn, heavy rainfall will be the primary tstorm parameter to affect the ILM CWA. If enough precip loading occurs, then wet microbursts may become an issue. As for max/min temps, just stayed with the meshing of the various Model MOS Guidance which gives widespread 70s for tonights lows and lower 90s for Sat highs and only mid-upper 80s along the immediate coast given local SSTS are in the 80-85 range now. && .SHORT TERM /SATURDAY NIGHT THROUGH SUNDAY NIGHT/... As of 300 PM Friday...Slow moving cold front will move into the region as the period begins with showers and thunderstorms likely ongoing. There will be an abundance of deep moisture for much of the period. Precipitable water values rise to almost 2.25 inches Sat night into Sun. Surface based instability will be lacking Sat night but convergence along the weak surface boundary as well as the presence of outflows in a moist, conditionally unstable environment should maintain at least some nocturnal convection. In addition there will be a little bit of shortwave energy approaching from the southwest which should lead to an increase in PVA after midnight. Storm coverage will be highest along the coast but everywhere will have at least a chance of showers and thunderstorms overnight. Front and deep moisture remain in the area Sun, although the 5h trough and drier air to the northwest start moving into northwestern portions of the forecast area later in the day. This will likely curtail convection in these areas but closer to the coast coverage will be higher. There will be another in a stream of shortwaves within the vorticity channel that spreads some PVA into the area on Sun. Combined with surface heating this should light off another round of convection. Storm motion will be around 15 kt which should prevent any 1 storm from posing a flooding risk however, training storms could pose a problem. Storms that develop will be very efficient at producing rainfall having warm cloud layers on the order of 13k-14k ft deep. While severe weather is unlikely given vertical profiles/limited shear a wet microburst from a storm cannot be ruled out. Still the main concern Sun will be flooding and not strong to severe storms. Dry air spreads in from the northwest late Sun and Sun night with most if not all convection shifting off the coast by midnight. Push of dry air is significant with pwats forecast to drop over an inch from 18Z Sun to 06Z Sun night. Some convection just off the coast cannot be ruled out late Sun night but wind direction/storm motion would tend to push any activity off the coast and thus pop after midnight is unlikely. Temperatures Sat night will run well above climo while temps Sun and Sun night will be near climo. && .LONG TERM /MONDAY THROUGH FRIDAY/... As of 300 PM Friday...Mid level troughiness Monday sharpens through Tuesday or Wednesday. Initially this will be a dry westerly flow Monday but a slightly more moisture-laden WSW flow Tuesday. Daytime temperatures will be held a bit below climatology through this time frame. The trough axis appears to swing through on Wednesday bringing a more decided drying. The rest of the period will be characterized by a building upper ridge over the Southeast and Bahamas. This will mark a transition back towards seasonable temperatures and isolated convection mainly during the diurnal maximum. && .AVIATION /00Z SATURDAY THROUGH WEDNESDAY/... As of 00Z...A few spot showers from earlier in the day have dissipated. Convective cloud debris continues to work across the area from the SW while more clouds well upstream continue to work in our direction. We expect VFR through the first part of the overnight. A stiff nocturnal jet will keep things well mixed overnight and we expect gusts around 20 kt to continue for the coastal terminals with winds backing down to 10 to 15 kt at KFLO and KFLO this eve. The direction will be SW. Expect winds of 15 to 25 kt on Sat, again from the SW. Model profiles continue to show an inversion 1-2 kft above the surface developing overnight and given what transpired last night, went ahead to include stratus near 1kft with ceilings at all the terminals in the 08-09z through about 13z. Sat is expected to be an unsettled day with numerous thunderstorms developing during the afternoon and then persisting into the nighttime hours. These thunderstorms will have the potential for significant flight restrictions. At this time included a prevailing group for thunderstorms after 20-22z at all the terminals. Extended Outlook...MVFR/IFR conditions are possible in thunderstorms Saturday night and into Sunday. Thunderstorms are expected to be most numerous Saturday evening and overnight. && .MARINE... NEAR TERM /THROUGH Saturday/... As of 300 PM Friday...Marine conditions will continue to erode thruout this period with SCEC conditions developing this evening and further eroding to SCA conditions after midnight tonight. This a result of the sfc pg, that continues to tighten as a sfc cold front drops southeast into the western Carolinas late tonight. At the same time, the Cindy remnants, will move along this cold front, reaching the DELMARVA coast Sat morning. Wind directions will run SSW-SW at 10 to 20 kt speeds thru this evening and veer slightly to SW-WSW at 15 to 25 kt speeds toward daybreak Sat and continue thru daylight Sat and into Sat Evening. Wind driven waves at 3 to 5 second periods will dominate the significant seas and should peak in the 3 to 6 foot range with a few 7 footers off Cape Fear and Romain respectively. Moderate to strong longshore currents will become apparent, especially south of Cape Fear to Murrells Inlet. SHORT TERM /SATURDAY NIGHT THROUGH SUNDAY NIGHT/... As of 300 PM Friday...Will continue to carry small craft advisory headline Sat night but hazard will be marginal at best. Front moving into the area combined with Bermuda High will tighten the gradient and speeds will increase to a solid 20 kt. Sustained 25 kt may be hard to come by and highest seas may end up closer to 5 ft than 6 ft but given at least some uncertainty with respect to the strength of the surface features will maintain the headline unchanged. Bermuda High remains in control Sun with southwest winds continuing, though in a weaker state as the front slowly moves closer and the high retreats east. Winds and seas will gradually decrease Sun into Sun night with flow becoming offshore late in the period as the surface boundary slips east of the waters. LONG TERM /MONDAY THROUGH WEDNESDAY/... As of 300 PM Friday...Not a typical summertime pattern in place for most of the period. A sharpening mid level trough will be in place. A series of weak surface boundaries may come through but with only very minor fluctuations of wind direction, though a northerly component will dominate. Wind speeds never really look to exceed 10kt by much though a few higher gusts will be possible. Seas will average 2 to occasionally 3 ft with near shore wave shadowing much more pronounced than usual this time of year where SW winds much more common. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...Beach Hazards Statement through Saturday evening for SCZ054- 056. NC...Beach Hazards Statement through Saturday evening for NCZ106- 108. Coastal Flood Advisory until 11 PM EDT this evening for NCZ107. MARINE...Small Craft Advisory from midnight tonight to 6 AM EDT Sunday for AMZ250-252-254-256. && $$ NEAR TERM...DCH SHORT TERM...MBB LONG TERM...III AVIATION...RJD is the U.S. government's official web portal to all federal, state and local government web resources and services.